The application is base on application No. 11-93123 filed in Japan on Mar. 31, 1999, the contents of which is incorporated hereinto by reference.
This invention relates to a method of fabrication for the output section of a solar battery.
The structure aid method of fabrication of a prior art solar battery output section is described in Japanese Non-examined Patent Publication HEI 7-231012 (1995). The fabrication method cited in this application has a process step to fix metal foil to output terminals on the front side of a solar battery, a process step to form a protective film from thermo-plastic resin on top of the solar battery including the metal foil, and a process step to provide openings formed by heating in the protective film above the metal foil using a device such as a soldering iron.
Another prior art solar battery output section structure and method of fabrication is described in Japanese Non-examined Patent Publication HEI 10-256578 (1998). The fabrication method cited in this application has a process step to provide openings through the solar battery and through output terminals on the front side of the solar battery, a process step to attach metal foil over the openings on the back side of the solar battery, and a process step to establish conductive paste inside the openings to electrically connect output terminals and metal foil.
For these types of prior art structures and methods of fabrication, the following problems exist. In the structure and method 6f fabrication cited in Japanese Non-examined Patent Publication HEI 7-231015 (1995) above, openings are provided by heating protective film above the metal foil using a device such as a soldering iron. As a result, residue of solidified thermoplastic resin remain within the openings after their heat formation. Consequently, when leads are solder attached, sufficiently strong connections cannot be obtained because of the thermo-plastic resin residue. Further, providing openings by heating with a device such as a soldering iron does not lend itself to manufacturability.
The structure and method of fabrication described in Japanese Non-examined Patent Publication HEI 10-256578 (1998) electrically connects front side output terminals to conductive paste disposed within openings. Compared with electrical connection by direct contact of metal foil with the output terminals, this system cannot obtain sufficiently low electrical resistance.
The present invention was developed to solve these types of problems. It is thus an object of the present invention to provide a method of solar battery output section fabrication which is efficient for manufacture and results in low electrical resistance values.
The above and further objects and features of the invention will more fully be apparent from the following detailed description with accompanying drawings.
This invention is characterized by a process step to attach metal foil on output terminals formed on the front side of a substrate, and a process step to cut-out openings to the metal foil from the back side of the substrate with a periphery cutter (analogous to a cookie cutter).
Further, this invention is characterized as well by a process step to attach metal foil on output terminals formed on the front side of a substrate, a process step to form a front side protective film on the substrate including the metal foil, and a process step to cut-out openings to the metal foil from above the protective film on the front side with a periphery cutter.
Still further, this invention is characterized by a process step to establish conductive paste, which forms output terminals, on the front side of a substrate, a process step to establish a resin film which covers the conductive paste, and a process step to cut-out openings to the conductive paste from the back side of the substrate with a periphery cutter.
In the method described above, solar battery output can be taken from the back side by providing output path openings, which are cut-out with a periphery cutter from the back side of the substrate to the metal foil. Since the back side of the metal foil is exposed within the openings, electrical connection to the foil via material such as solder can produce sufficiently low electrical resistance connections. In addition, since openings are cut-out with a periphery cutter, the method is efficient for manufacture.
Further in the method described above, solar battery output can be taken from the front side by providing output path openings, which are cut-out with a periphery cutter from the front side of the substrate to the metal foil. Since the front side of the metal foil is exposed within the openings, electrical connection to the foil via material such as solder can produce sufficiently low electrical resistance connections. In addition, since openings are cut-out with a periphery cutter, the method is efficient for manufacture.
Finally, in the method described above, solar battery output can be taken from the back side by providing output path openings, which are cut-out with a periphery cutter from the back side of the substrate to the conductive paste. Since the back side of the conductive paste is exposed within the openings, electrical connection to the conductive paste via material such as conductive resin can produce sufficiently low electrical resistance connections. In addition, since openings are cut-out with a periphery cutter, the method is efficient for manufacture.